arch/s390/mm/vmem.c

   1 /*
   2  *    Copyright IBM Corp. 2006
   3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   4  */
   5
   6 #include <linux/bootmem.h>
   7 #include <linux/pfn.h>
   8 #include <linux/mm.h>
   9 #include <linux/module.h>
  10 #include <linux/list.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/slab.h>
  13 #include <linux/memblock.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/setup.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/sections.h>
  19
  20 static DEFINE_MUTEX(vmem_mutex);
  21
  22 struct memory_segment {
  23         struct list_head list;
  24         unsigned long start;
  25         unsigned long size;
  26 };
  27
  28 static LIST_HEAD(mem_segs);
  29
  30 static void __ref *vmem_alloc_pages(unsigned int order)
  31 {
  32         if (slab_is_available())
  33                 return (void *)__get_free_pages(GFP_KERNEL, order);
  34         return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
  35 }
  36
  37 static inline pud_t *vmem_pud_alloc(void)
  38 {
  39         pud_t *pud = NULL;
  40
  41 #ifdef CONFIG_64BIT
  42         pud = vmem_alloc_pages(2);
  43         if (!pud)
  44                 return NULL;
  45         clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
  46 #endif
  47         return pud;
  48 }
  49
  50 static inline pmd_t *vmem_pmd_alloc(void)
  51 {
  52         pmd_t *pmd = NULL;
  53
  54 #ifdef CONFIG_64BIT
  55         pmd = vmem_alloc_pages(2);
  56         if (!pmd)
  57                 return NULL;
  58         clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
  59 #endif
  60         return pmd;
  61 }
  62
  63 static pte_t __ref *vmem_pte_alloc(unsigned long address)
  64 {
  65         pte_t *pte;
  66
  67         if (slab_is_available())
  68                 pte = (pte_t *) page_table_alloc(&init_mm, address);
  69         else
  70                 pte = alloc_bootmem_align(PTRS_PER_PTE * sizeof(pte_t),
  71                                           PTRS_PER_PTE * sizeof(pte_t));
  72         if (!pte)
  73                 return NULL;
  74         clear_table((unsigned long *) pte, _PAGE_INVALID,
  75                     PTRS_PER_PTE * sizeof(pte_t));
  76         return pte;
  77 }
  78
  79 /*
  80  * Add a physical memory range to the 1:1 mapping.
  81  */
  82 static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
  83 {
  84         unsigned long end = start + size;
  85         unsigned long address = start;
  86         pgd_t *pg_dir;
  87         pud_t *pu_dir;
  88         pmd_t *pm_dir;
  89         pte_t *pt_dir;
  90         int ret = -ENOMEM;
  91
  92         while (address < end) {
  93                 pg_dir = pgd_offset_k(address);
  94                 if (pgd_none(*pg_dir)) {
  95                         pu_dir = vmem_pud_alloc();
  96                         if (!pu_dir)
  97                                 goto out;
  98                         pgd_populate(&init_mm, pg_dir, pu_dir);
  99                 }
 100                 pu_dir = pud_offset(pg_dir, address);
 101 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
 102                 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
 103                     !(address & ~PUD_MASK) && (address + PUD_SIZE <= end)) {
 104                         pud_val(*pu_dir) = __pa(address) |
 105                                 _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE |
 106                                 (ro ? _REGION_ENTRY_PROTECT : 0);
 107                         address += PUD_SIZE;
 108                         continue;
 109                 }
 110 #endif
 111                 if (pud_none(*pu_dir)) {
 112                         pm_dir = vmem_pmd_alloc();
 113                         if (!pm_dir)
 114                                 goto out;
 115                         pud_populate(&init_mm, pu_dir, pm_dir);
 116                 }
 117                 pm_dir = pmd_offset(pu_dir, address);
 118 #if defined(CONFIG_64BIT) && !defined(CONFIG_DEBUG_PAGEALLOC)
 119                 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
 120                     !(address & ~PMD_MASK) && (address + PMD_SIZE <= end)) {
 121                         pmd_val(*pm_dir) = __pa(address) |
 122                                 _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE |
 123                                 _SEGMENT_ENTRY_YOUNG |
 124                                 (ro ? _SEGMENT_ENTRY_PROTECT : 0);
 125                         address += PMD_SIZE;
 126                         continue;
 127                 }
 128 #endif
 129                 if (pmd_none(*pm_dir)) {
 130                         pt_dir = vmem_pte_alloc(address);
 131                         if (!pt_dir)
 132                                 goto out;
 133                         pmd_populate(&init_mm, pm_dir, pt_dir);
 134                 }
 135
 136                 pt_dir = pte_offset_kernel(pm_dir, address);
 137                 pte_val(*pt_dir) = __pa(address) |
 138                         pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
 139                 address += PAGE_SIZE;
 140         }
 141         ret = 0;
 142 out:
 143         return ret;
 144 }
 145
 146 /*
 147  * Remove a physical memory range from the 1:1 mapping.
 148  * Currently only invalidates page table entries.
 149  */
 150 static void vmem_remove_range(unsigned long start, unsigned long size)
 151 {
 152         unsigned long end = start + size;
 153         unsigned long address = start;
 154         pgd_t *pg_dir;
 155         pud_t *pu_dir;
 156         pmd_t *pm_dir;
 157         pte_t *pt_dir;
 158         pte_t  pte;
 159
 160         pte_val(pte) = _PAGE_INVALID;
 161         while (address < end) {
 162                 pg_dir = pgd_offset_k(address);
 163                 if (pgd_none(*pg_dir)) {
 164                         address += PGDIR_SIZE;
 165                         continue;
 166                 }
 167                 pu_dir = pud_offset(pg_dir, address);
 168                 if (pud_none(*pu_dir)) {
 169                         address += PUD_SIZE;
 170                         continue;
 171                 }
 172                 if (pud_large(*pu_dir)) {
 173                         pud_clear(pu_dir);
 174                         address += PUD_SIZE;
 175                         continue;
 176                 }
 177                 pm_dir = pmd_offset(pu_dir, address);
 178                 if (pmd_none(*pm_dir)) {
 179                         address += PMD_SIZE;
 180                         continue;
 181                 }
 182                 if (pmd_large(*pm_dir)) {
 183                         pmd_clear(pm_dir);
 184                         address += PMD_SIZE;
 185                         continue;
 186                 }
 187                 pt_dir = pte_offset_kernel(pm_dir, address);
 188                 *pt_dir = pte;
 189                 address += PAGE_SIZE;
 190         }
 191         flush_tlb_kernel_range(start, end);
 192 }
 193
 194 /*
 195  * Add a backed mem_map array to the virtual mem_map array.
 196  */
 197 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 198 {
 199         unsigned long address = start;
 200         pgd_t *pg_dir;
 201         pud_t *pu_dir;
 202         pmd_t *pm_dir;
 203         pte_t *pt_dir;
 204         int ret = -ENOMEM;
 205
 206         for (address = start; address < end;) {
 207                 pg_dir = pgd_offset_k(address);
 208                 if (pgd_none(*pg_dir)) {
 209                         pu_dir = vmem_pud_alloc();
 210                         if (!pu_dir)
 211                                 goto out;
 212                         pgd_populate(&init_mm, pg_dir, pu_dir);
 213                 }
 214
 215                 pu_dir = pud_offset(pg_dir, address);
 216                 if (pud_none(*pu_dir)) {
 217                         pm_dir = vmem_pmd_alloc();
 218                         if (!pm_dir)
 219                                 goto out;
 220                         pud_populate(&init_mm, pu_dir, pm_dir);
 221                 }
 222
 223                 pm_dir = pmd_offset(pu_dir, address);
 224                 if (pmd_none(*pm_dir)) {
 225 #ifdef CONFIG_64BIT
 226                         /* Use 1MB frames for vmemmap if available. We always
 227                          * use large frames even if they are only partially
 228                          * used.
 229                          * Otherwise we would have also page tables since
 230                          * vmemmap_populate gets called for each section
 231                          * separately. */
 232                         if (MACHINE_HAS_EDAT1) {
 233                                 void *new_page;
 234
 235                                 new_page = vmemmap_alloc_block(PMD_SIZE, node);
 236                                 if (!new_page)
 237                                         goto out;
 238                                 pmd_val(*pm_dir) = __pa(new_page) |
 239                                         _SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE |
 240                                         _SEGMENT_ENTRY_CO;
 241                                 address = (address + PMD_SIZE) & PMD_MASK;
 242                                 continue;
 243                         }
 244 #endif
 245                         pt_dir = vmem_pte_alloc(address);
 246                         if (!pt_dir)
 247                                 goto out;
 248                         pmd_populate(&init_mm, pm_dir, pt_dir);
 249                 } else if (pmd_large(*pm_dir)) {
 250                         address = (address + PMD_SIZE) & PMD_MASK;
 251                         continue;
 252                 }
 253
 254                 pt_dir = pte_offset_kernel(pm_dir, address);
 255                 if (pte_none(*pt_dir)) {
 256                         unsigned long new_page;
 257
 258                         new_page =__pa(vmem_alloc_pages(0));
 259                         if (!new_page)
 260                                 goto out;
 261                         pte_val(*pt_dir) =
 262                                 __pa(new_page) | pgprot_val(PAGE_KERNEL);
 263                 }
 264                 address += PAGE_SIZE;
 265         }
 266         memset((void *)start, 0, end - start);
 267         ret = 0;
 268 out:
 269         return ret;
 270 }
 271
 272 void vmemmap_free(unsigned long start, unsigned long end)
 273 {
 274 }
 275
 276 /*
 277  * Add memory segment to the segment list if it doesn't overlap with
 278  * an already present segment.
 279  */
 280 static int insert_memory_segment(struct memory_segment *seg)
 281 {
 282         struct memory_segment *tmp;
 283
 284         if (seg->start + seg->size > VMEM_MAX_PHYS ||
 285             seg->start + seg->size < seg->start)
 286                 return -ERANGE;
 287
 288         list_for_each_entry(tmp, &mem_segs, list) {
 289                 if (seg->start >= tmp->start + tmp->size)
 290                         continue;
 291                 if (seg->start + seg->size <= tmp->start)
 292                         continue;
 293                 return -ENOSPC;
 294         }
 295         list_add(&seg->list, &mem_segs);
 296         return 0;
 297 }
 298
 299 /*
 300  * Remove memory segment from the segment list.
 301  */
 302 static void remove_memory_segment(struct memory_segment *seg)
 303 {
 304         list_del(&seg->list);
 305 }
 306
 307 static void __remove_shared_memory(struct memory_segment *seg)
 308 {
 309         remove_memory_segment(seg);
 310         vmem_remove_range(seg->start, seg->size);
 311 }
 312
 313 int vmem_remove_mapping(unsigned long start, unsigned long size)
 314 {
 315         struct memory_segment *seg;
 316         int ret;
 317
 318         mutex_lock(&vmem_mutex);
 319
 320         ret = -ENOENT;
 321         list_for_each_entry(seg, &mem_segs, list) {
 322                 if (seg->start == start && seg->size == size)
 323                         break;
 324         }
 325
 326         if (seg->start != start || seg->size != size)
 327                 goto out;
 328
 329         ret = 0;
 330         __remove_shared_memory(seg);
 331         kfree(seg);
 332 out:
 333         mutex_unlock(&vmem_mutex);
 334         return ret;
 335 }
 336
 337 int vmem_add_mapping(unsigned long start, unsigned long size)
 338 {
 339         struct memory_segment *seg;
 340         int ret;
 341
 342         mutex_lock(&vmem_mutex);
 343         ret = -ENOMEM;
 344         seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 345         if (!seg)
 346                 goto out;
 347         seg->start = start;
 348         seg->size = size;
 349
 350         ret = insert_memory_segment(seg);
 351         if (ret)
 352                 goto out_free;
 353
 354         ret = vmem_add_mem(start, size, 0);
 355         if (ret)
 356                 goto out_remove;
 357         goto out;
 358
 359 out_remove:
 360         __remove_shared_memory(seg);
 361 out_free:
 362         kfree(seg);
 363 out:
 364         mutex_unlock(&vmem_mutex);
 365         return ret;
 366 }
 367
 368 /*
 369  * map whole physical memory to virtual memory (identity mapping)
 370  * we reserve enough space in the vmalloc area for vmemmap to hotplug
 371  * additional memory segments.
 372  */
 373 void __init vmem_map_init(void)
 374 {
 375         unsigned long ro_start, ro_end;
 376         struct memblock_region *reg;
 377         phys_addr_t start, end;
 378
 379         ro_start = PFN_ALIGN((unsigned long)&_stext);
 380         ro_end = (unsigned long)&_eshared & PAGE_MASK;
 381         for_each_memblock(memory, reg) {
 382                 start = reg->base;
 383                 end = reg->base + reg->size - 1;
 384                 if (start >= ro_end || end <= ro_start)
 385                         vmem_add_mem(start, end - start, 0);
 386                 else if (start >= ro_start && end <= ro_end)
 387                         vmem_add_mem(start, end - start, 1);
 388                 else if (start >= ro_start) {
 389                         vmem_add_mem(start, ro_end - start, 1);
 390                         vmem_add_mem(ro_end, end - ro_end, 0);
 391                 } else if (end < ro_end) {
 392                         vmem_add_mem(start, ro_start - start, 0);
 393                         vmem_add_mem(ro_start, end - ro_start, 1);
 394                 } else {
 395                         vmem_add_mem(start, ro_start - start, 0);
 396                         vmem_add_mem(ro_start, ro_end - ro_start, 1);
 397                         vmem_add_mem(ro_end, end - ro_end, 0);
 398                 }
 399         }
 400 }
 401
 402 /*
 403  * Convert memblock.memory  to a memory segment list so there is a single
 404  * list that contains all memory segments.
 405  */
 406 static int __init vmem_convert_memory_chunk(void)
 407 {
 408         struct memblock_region *reg;
 409         struct memory_segment *seg;
 410
 411         mutex_lock(&vmem_mutex);
 412         for_each_memblock(memory, reg) {
 413                 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
 414                 if (!seg)
 415                         panic("Out of memory...\n");
 416                 seg->start = reg->base;
 417                 seg->size = reg->size;
 418                 insert_memory_segment(seg);
 419         }
 420         mutex_unlock(&vmem_mutex);
 421         return 0;
 422 }
 423
 424 core_initcall(vmem_convert_memory_chunk);